METALLURGY OF IRON AND STEEL.
Rivet Rods from Heat 10,168, which showed the Greatest Differences in the Tensile Strength of the Annealed Bars.
Nature of Sample. Ultimate strength ; pounds per sq. Inch. Composition ; per cent.
Natural. Annealed. 0. P. 8. Mn.
Preliminary test . . .... 52280 53090 mm .12 ,12 .It .013 .013 .«§ .024 .010 .034 .20 .30 .80
Average of strongest three bars of % inch diameter . . . Average of weakest three bars of % inch diameter . . . 60680 48680
cause such metal remains liquid for a long time, but even uiider these conditions separation of the impurities does not always occur. This will he shown by Tables XIII-L and XIII-M, which give the results of investigations by The Pennsylvania Steel Company. The data on carbon in Table XIII-L are of little importance, for a color determination is well-nigh worthless on high steels.
The determinations of carbon in Table XIII-M are made by combustion and are accurate, and they show a considerable variation in the distribution of this element; this might be expected when a large proportion is present, and its hold upon the iron correspondingly less firm. The sulphur and phosphorus are regular, the variations in the purer metal being almost within the limits of error. In the ingot of medium phosphorus, the percentage of variation is no more than in the others, but the actual range is greater. Although this would follow naturally, it is possible to show, by an incident which happened under my own observation, that concentration does not always occur, even in the case of impure steels.
A 50-ton acid open-hearth charge had been made containing .46 per cent, of carbon, together with unusually high manganese, phosphorus, and silicon. The ingots had a cross-section of 16"x20", and weighed 4000 pounds each. In loading them, one fell over and "bled" at the top. The amount of liquid metal thus lost did not exceed 25 pounds, although the cavity was completely emptied, so that if segregation existe.d to any considerable extent it "should appear in this metal which remained liquid to the last. Table Xni-iN~ will show that little segregation had taken place. SEC. Xlllg.—Acid open-hearth nickel steel.—It is the impres-